The dimensions and electrical contacts of a light radiation source, e.g. a lamp for general illumination purposes or for special lighting purposes, are often standardized. The term “light” refers to any magnetic radiation having a wavelength between 250 and 900 nm. However, the wattage, spectral distribution, and degree of efficiency in producing light radiation may be different for identical looking lamps, and hence the radiation intensity is different as well. In case of replacement of a lamp that has become unusable, the operation of a system for general illumination or for special lighting purposes is negatively affected if a lamp with either too high or too low a radiation intensity is installed. For example, a timer is often set in order to choose the degree of tanning in the case of a solarium. When the lamps of a solarium are replaced, installing lamps with a too high UV radiation output would cause sunburn of the user's skin. UV lamps used for disinfection purposes with a too low UV radiation output will result in an insufficient degree of disinfection. When using UV or infrared lamps, for example for medical purposes, a too low or too high luminous intensity of the lamps after incorrect lamp replacement may result in an improper treatment of the patient. An incorrect replacement of lamps for general illumination purposes may result in an insufficient level of illumination on the one hand or a too high power consumption and possibly damage to the lampholder on the other hand.
In mercury vapor discharge lamps, mercury constitutes the primary component for the generation of ultraviolet (UV) light. A luminescent layer comprising a luminescent material may be present on an inner wall of the discharge vessel to convert UV to other wavelengths, for example to UV-B and UV-A for tanning purposes (sun panel lamps) or to visible radiation for general illumination purposes or for the illumination of display devices. Such discharge lamps are therefore also referred to as fluorescent lamps. The discharge vessel of a low-pressure mercury vapor discharge lamp is usually circular and comprises both elongate and compact embodiments. Generally, the tubular discharge vessel of a compact fluorescent lamp comprises a collection of relatively short straight parts having a relatively small diameter; the straight parts being connected together by means of so-called bridge parts or via bent parts. Generally, means for maintaining a discharge in the discharge space are electrodes arranged in the discharge space.
The Canadian patent application CA 2 403 463 A1 describes a method and a device for operating a UV-radiation source. A UV-radiation source is disclosed, having an identification element that can be interrogated electrically and that is connected to the electrical connections of the radiation source, in parallel to the heating coil. Before a start of operation of the UV-radiation source, the UV lamp is identified by the identification element and, if the result of the identification is negative, operation of the lamp is prevented. Operation of the UV-radiation source is thus prevented if a mistake was made during lamp replacement.
It is a disadvantage of the prior art identification system that a proper functioning of the identification system is prohibited if the impedance of the lamp electrode is relatively low, for example with high signal frequencies in the range of 3-30 MHz, since the identification element cannot be interrogated reliably any more.